Ecology of the active soil microfauna (Protozoa, Metazoa) of Wilkes Land, East Antarctica

Active ciliates, testate amoebae, nematodes, rotifers and tardigrades were examined in fresh and preserved fellfield, moss and ornithogenic soil samples of Wilkes Land. Direct counting was used to investigate abundances, community structures and protozoan diversity. Twenty-six ciliate species (nine first records for continental Antarctica, one undescribed) and five testacean species (three new records) were found. Two Colpoda species were active, further disproving Smith's hypothesis that this genus is absent in continental Antarctica. Animal frequencies varied between habitats but every group occurred in at least 74% of the samples, rotifers (95%) and testaceans (92%) being most frequent. Highest abundances were recorded in moss: 354 ciliates/g dry soil (19 species), 671 testaceans (5 species), 513 nematodes, 1,311 rotifers and 4,607 tardigrades, which thus dominated. Rotifers were most abundant in the other habitats. The microfauna was not randomly distributed because individual numbers were often strongly intercorrelated. Water and organic matter content were relevant environmental parameters; air temperature and pH probably had indirect effects. Received:28 August 1996 / Accepted:23 November 1996